The VA Office of Patient Centered Care and Cultural Transformation's Whole Health initiative promotes the use of complementary and integrative health (CIH) approaches with traditional medical care to help Veterans achieve meaningful life goals and improved functioning. Equine-facilitated therapy (EFT), an animal-assisted form of CIH, is increasingly available to Veterans within the VA. Horses have extreme sensitivity to the emotional states, behaviors, and intentions of their herds and other animals, including humans, and mirror body language and respond to subtle nonverbal cues. As such, horses have the capacity to provide immediate feedback about a people's emotional and behavioral states. This capacity affords people opportunities to become more emotionally self-aware and, with guidance from EFT facilitators, learn how to regulate emotions and become calmer and more patient, attentive, and confident to gain the horses' cooperation. Participants in EFT are encouraged to apply what they have learned from their equine experiences to their relationships with people. Since high quality social functioning depends on effective regulation of one's emotions, EFT offers a novel way in which to improve the social functioning of Veterans with mental health concerns. VAs are increasingly embracing EFT as a CIH. However, carefully conducted, scientifically valid research about EFT has not been conducted. Existing peer-reviewed research about EFT for mental health is very limited, of poor methodological quality, and not focused on adults. None of it targets social functioning as a main outcome. This small randomized controlled pilot test proposes to examine an innovative EFT called The Equus Effect (TEE) as a complement to Veterans' existing VA mental health services to improve social functioning. TEE aims to improve Veterans' social functioning by developing their emotion regulation and interpersonal skills through therapeutic interactions with horses. This study will evaluate 1) the feasibility of study procedures, assessments, and outcomes, 2) the fidelity of experimental and control interventions, and 3) the acceptability of the interventions to Veterans and their mental health clinicians using mixed quantitative-qualitative methods. The study has the potential to lend initial credibility to the therapeutic claims of this increasingly popular CIH. Should data indicate that TEE and methods to study its effects are feasible and acceptable, it will set the stage for a RR&D IIR proposal to test the efficacy of TEE in a multi-site randomized controlled trial.